Magnetic nanostructures and interfaces are at the heart of information technologies and spintronics. Typical dimensions of magnetic bits are in the sub-100nm region. In addition novel magnetoelectronics devices such as magnetic random access memory junctions are operated on the sub-µm length scale. Typical magnetic switching times are approaching the sub-100 ps timescale. An understanding of static and dynamic magnetic properties of such low-dimensional structures is only accessible to spectro-microscopy tools capable of appropriate lateral and temporal resolution. Using x-ray photoemission microscopy we investigate electronic structure and magnetic responses of single ferromagnetic nanoparticles. The figure shows spectra and magnetic responses of chemically synthesized Fe nanocubes with 18nm edgelength. Magnetic states and interactions of monomers, dimers, and trimers can be analyzed for different particle arrangements. Comparing experimental data to micromagnetic simulations we reveal the influence of dipolar coupling and intrinsic magnetic anisotropy on the magnetic properties of individual nanomagnets and their configurations.
Kronast, F.; Friedenberger, N.; Ollefs, K.; Gliga, S.; Tati-Bismaths, L.; Thies, R.; Ney, A.; Weber, R.; Hassel, C.; Römer, F.M.; Trunova, A.V.; Wirtz, C.; Hertel, R.; Dürr, H.A.; Farle, M. Nano Letters 11 (2011), p. 1710-1715